Perhaps a picture of the boiler will help, I,m looking for instructions to properly drain the antifreeze from the hot water heating. I have a compressor, I've heard of some plumbers using that to push out water from the lines. Also is a rust inhibitor necessary?
I'd like to do the job correctly. From what I learned so far I think by letting the boiler cool completely, then turn off the zone feed valves, connect a hose to the drain on the right of the boiler, I think the lower left is just domestic hot water. then open one zone at a time to push the antifreeze out using the autofil lever, then close the zone release the autofil lever, and copy for the next zone. When done colse the drain, open the zones and fire up to boiler. sound reasonable ?